OPC 31260 is a Vasopressin receptor antagonist marketed by Otsuka. It is a benzazepine derivative that antagonizes the binding of arginine vasopressin (AVP) to vasopressin receptors located in the liver (V1; IC50 = 1.2 µM) and kidney (V2; IC50 = 14 nM). In Japan, OPC 31260 was approved in October 2006 for hyponatremia (low blood sodium levels) caused by syndrome of inappropriate antidiuretic hormone (SIADH) due to ADH producing tumors.

The present study was undertaken to determine whether the non-peptide V2 arginine vasopressin (AVP) antagonist 5-dimethylamino- 1[4-(2-methylbenzoylamino)benzoyl]-2,3,4,5-tetrahydro-1H-benzazepi ne hydrochloride (OPC-31260) produces water diuresis and improves hyponatremia in patients with the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). Eleven patients (9 males and 2 females, 64 +/- 3.5 yr) with SIADH were included in the present protocol, which was comprised of 3 successive days. Day 1 was a control day, and on days 2 and 3 OPC-31260 was administered intravenously. Five blood and urine collections were made at 1-2 h intervals during the 6 h observation period each day. A single administration of 0.25 and 0.5 mg/kg OPC-31260 increased the 4 h cumulative urine volume and decreased urinary osmolality to below 225 mOsm/kg H2O. Such a diuretic effect was independent of an increase in urinary solute excretions. This aquaresis by 0.

Ectopic antidiuretic hormone syndrome is a medical emergency characterized by dilutional hyponatremia. Clinical effectiveness of the vasopressin V2 receptor antagonist mozavaptan was evaluated in 16 patients. In short-term (7-day) treatment with the drug, serum sodium concentration (mean ± standard deviation) significantly (P = 0.002) increased from 122.8 ± 6.7 to 133.3 ± 8.3 mEq/l, and symptoms due to hyponatremia were improved. On the basis of these results, mozavaptan (Physuline(®)) was approved as an orphan drug for the treatment of the syndrome in 2006 in Japan. During the 43 months following its launch, 100 patients have been treated with the drug; overall clinical effects of the drug were found similar to those of this clinical trial. Clinically, mozavaptan may allow hyponatremic patients to be treated by aggressive cancer chemotherapy with platinum-containing drugs. Moreover, the drug may free patients from strict fluid-intake restrictions and thereby improve their quality of life.

The effects of the non-peptide vasopressin V2 receptor antagonist, 5-dimethylamino-1-[4-(2-methylbenzoylamino)benzoyl]-2,3,4,5-tetrah ydro-1 H-benzazepine hydrochloride (OPC-31260) on the cerebral oedema induced by subarachnoid haemorrhage were studied in rats. Subarachnoid haemorrhage induced significant water retention after water loading, increased the brain content of water and Na+ and increased plasma vasopressin levels. The water retention and brain water and Na+ accumulation were prevented by OPC-31260 administration, but the plasma vasopressin levels were further enhanced by OPC-31260. These results demonstrate the important role of vasopressin in the development of antidiuresis and disturbances in brain water and electrolyte balance in response to subarachnoid haemorrhage. The subarachnoid haemorrhage-induced cerebral oedema was significantly reduced following oral OPC-31260 administration. The protective mechanism exerted by OPC-31260 stems from its influence on renal tubular function: it blocks the renal vasopressin V2 receptors.

4.Prevention of hypoxic brain oedema by the administration of vasopressin receptor antagonist OPC-31260.

The numerous situations which can result in cerebral hypoxic damage occur in newborn infants and in the elderly. In research aimed at more effective therapeutic intervention in ischaemic disorders of the brain, the animal model used and the principles of the causal therapy should be better outlined. The effects of the non-peptide AVPR (V2) antagonist 5-dimethylamino-1-[4-(2-methylbenzoylamino) benzoyl]-2,3,4,5-tetrahydro-1H-benzazepine hydrochloride (OPC-31260) on the cerebral oedema induced by general cerebral hypoxia were studied in rats. The general cerebral hypoxia was produced by bilateral common carotid ligation in Sprague-Dawley rats of the CFY strain. By 6h after the ligation, half of the rats had died, but the survival rate was significantly higher following OPC-31260 administration. Electron microscopic examinations revealed typical ischaemic changes after the carotid ligation, and OPC-31260 treatment did not significantly reduce the hypoxic signs in the brain cortex; only a certain decrease in the pericapillary oedema was observed.